False twister



Dc. so, 195s H. A. SCHRENK l FALSE TWISTER Filed April 9. 1956 IN VENTORmslwzhJc/Zrefz ATTORNEY 2,866,311 FALSE rrwrsTER Hans Alwin Schrenk,Arnhem, Netherlands, assignor to American Enka Corporation, Enka, N. C.,a corporation of Delaware Application April 9, 1956, Serial No. 576,971Claims priority, application Netherlands April 21, 1955 Claims. (Cl.57'-77.3)

This invention relates to false twisting apparatus and more particularlyto an improved false twister for imparting superior curl tothermoplastic yarns. n

In the art of curling thermoplastic yarns and threads, it is known tointerpose a false twister between two twist stops and to impart curl tothe yarn in its run from o-ne twist stop to the false twister and totake the curl out again in the run of the yarn from the false twister to'the other twist stop. While the curl is in the yarn, it is set bysuccessive heating and cooling steps. In general, the linear speed atwhich the process may be conducted is related to the speed at which thefalse twister may be run. Thus a good deal of work has been done in aneffort to produce reliable false twisters capable of high speedoperation.

One of the more successful false twisters is made by providing arotatable body having opposite end portions provided with yarn channelsand a narrow intermediate waist between the end portions. In this typeof apparatus the yarn is led into one end portion at the axis ofrotation, through the channel which diverges from the axis of rotation,around the waist where the yarn slips, and into the channel of the otherend portion which converges toward the axis of rotation where the yarnemerges again.

lt is an object of the present invention to improve on the foregoingtype of false twister and more particularly to prevent relative slippagebetween the yarn and the waist thereof whereby stronger false twist maybe imparted to the yarn with resulting improvement in curl.

It is proposed according to the present invention to provide a falsetwister having end portions provided with yarn channels, said endportions being interconnected for rotation together and a waist portionbetween said end portions that is freely rotatable in relation to andcoaxially with the end portions.

Other objects and advantages of the invention will be apparent upon theconsideration of the following detailed description of a preferredembodiment thereof in conjunction with the annexed drawings, wherein:

Figure 1 is a perspective view of a false twister constructed inaccordance with the teachings of the present invention;

Figure 2 is a diametrical view in vertical section through the falsetwister of Figure 1; and

Figure 3 is a sectional view, somewhat enlarged, showing the preferredconstruction of one of the elements of the present invention.

Referring now in detail to the drawing, the false twister consists of arotatable body having an upper frustoconical end portion 11 and a lowerend portion 12 which is really a thick ange at the upper end of adriving sheave 13 for receiving a belt, not shown, for rotating the body10. The end portions 11 and 12 are interconnected by a stud 14 whichprojects from the end portion 12 and which is threaded into the centerof the base of the frusto-conical end portion 11. A stationary body 15supports centrally therein a yarn tube 16. Ball bearnted lStatesPatent/fio 2,866,31 1 Patented Dec.l 30,- 195g- 'ice ing races 17 and 18are mounted about the upper end of the tube 16 and the body 10 ismounted for free rotation on these bearings.

Within the ilange or lower end portion 12 there is a diagonal channel 19leading from a port 20 which is coaxial with the tube 16 to a port 21which is radially offset from the axis of the end portion 12 and thetube 16. The end portion 11 is provided with a port at 22 which'isfradially offset in respect of the axis of rotation'- of the body 10and this port is connected by a channel 23 to a port 24 at the top ofthe end portion 11, this port' being lcoaxial with the center line ofthe tube 16. For convenience in threading up, the number of channelsi'n' the end portions 12 and 11 may be in excess of one, two being shownin the embodiment of the invention depicted' in Figures 1 and 2.

Surrounding the stud or pin 14 which acts as a coni necting neck betweenend portions 11 and 12 there is a' collar 25. This collar is mounted onthe neck for free rotation by any friction-free arrangement known to theart. While the collar 25 is shown in Figure 2 as being' generallycylindrical, it is preferable to have-its outside surface somewhatconcave in relation to the axis of rotation. In other words, it ispreferred that the external surface of the collar be of somewhat smallerdiameter in the middle of the length than it is at the end, as shownmore clearly at collar 25a in Figure 3.

In use, the false twister of the present invention is supplied withthread coming in the direction of the arrow from a twist stop not shown.The yarn or thread passes through the tube 16 and through the channel19. It is then wrapped around the collar 25 which is mounted for freerotation about the pin 14. After wrapping at least 360 around collar 25,and preferably 720, the thread is led through the channel 23 and out ofthe false twister in the direction of the arrow to an upper twist stopnot shown. The body 1l) of the false twister is rotated by a beltfrictionally engaging the sheave 13. While end portions 11 and 12 andconnecting pin 14 rotate as a unit, the collar 25 is freely movable inrelation to the body 10 and its movement is controlled by the yarnrather than by the action of the sheave.

It is believed that the good results achieved by the present inventionmay be attributed to the fact that the collar 25 keeps the thread fromsliding longitudinally in its movement from the lower end portion 12 ofthe body 10 to the upper end portion 1l thereof. It is noted thatbecause of the use of the collar 25, rotation of the thread about itsown axis in its run between the ports 21' and 22 is reduced. In view ofthe fact that the thread does not appreciably move lengthwise or aboutits axis while in contact with the collar 25, the angle of wrap aroundthe pin 14 can be increased without appreciable inuence on threadtension. This has been found to improve the reliability of the falsetwister. The external coneavity of the surface of the collar 25 helps tocause the thread windings, if they exceed 360, to arrange themselvesside by side. Because of the tensions which are possible with this typeof apparatus, the ballooning which is common with this type of falsetwister is avoided.

Further the end portion of the false twisting device may have aconstruction different from that shown in the figures. For instance, thechannels in the said portions may extend parallel to the vertical centerline thereof or may diverge from the freely rotatable collar. Neither isit necessary for these channels to terminate at the bottom side of theend portion but they may end at the side of this element. In that case,however, it is desirable to round olf the bottom edge of the end portionin order to facilitate thel sliding of the thread over this edge.Finally the channels need not be duplicated in twofold n s u iirthezendportions, although this is preferred with a view to. Qhtaining a quietrotation of the spindle.

What is claimed is:

1. A false twister comprising a body including two end portions andanintermediate neck interconnecting them, said` portions having. yarnchannels extending lengthwise therethrough, means mounting said body`for rotation and a. collar freely rotatable co-axially about said` neck.

2. A false twister-comprising astationary tube, a body including two endportions interconnected, by a narrow neck, said end portions each havinga yarn channel therethrough, means mounting, said body for rotationabout said tube with one endv of one of said channels in registrywiththe end of said tube and a1 collar freely rotatable co-axially aboutsaid neck.

3. Atalse twister comprising'a stationary tube, a body including two endportions interconnectedv byy a narrow necka,collar, surrounding saidneck and freely rotatable with respect thereto, means mountingv one; ofsaidV end portions for free rotation coaxially about said tube, each i.

end portion having a yarn channel extending lengthwise therethrough, thechannels being at their endsadjacent the collar further from the axisthan at their otherends.

4. A false twister comprising a body including twogend. portions andaninterrnediate neck interconnecting-` them, Said` portions` having yarnchannels extendingv lengthwise y 4 therethrough, means mounting saidbody for rotation and an externally conca-ve collar freely' rotatableco-axially about said neck.

5. A false twister comprising a stationary tube, a body including twoend portions interconnected by a narrow neck, a collar surrounding said.neck and freely rotatable References Citedinthe tileof this patentUNITED STATES PATENTS 819,298 Martin May l, 1906 1,030,235. Finlay June.18, 1912 1,771,656 Roe` July 29, 1930 2,556,919 Hardacrexet al June 12,1951 FOREIGN PATENTS 161,887y Australia Mar. 11, 1955 Great. BritainJan. 6, 1954

